Improvement in balanced slide-valves



, of the steam-chest.

VUNITED STATES PATENT .GEEICE `GEORGE E. MoEsE, 0E PORTLAND, MAINE.

IMPROVEMENT IN BALANCED SLIDE-VALVES.

Specification forming part of Letters Patent No. 107,945, dated October4, 1870.

' Slide-Valves for Steam-Engines; and I do hereby declare the follwin gto be a full, clear, and exact description thereof, which will enableothers to make-and use my invention, reference being had to theaccompanying drawings, forming .part of this speciiication, in which-Figure l represents a section of the balanced slide-valve placed inposition in the steam-chest. Fig. 2 represents a plan of the balancedslide-valve of circular form. Fig. 3 represents a plan of qthe balancedslide-valve of rectangular form. v

In the following description I have `set forth the nature and principlesof said improvement, by which my invention may be distinguished fromothers of a similar class.

The valve is `shown as a simple rectangular or circular box havingsides, but neither top nor bottom. These sides are to be perpen-vdicular, or nearly so,\the bottom edges bear- I `ing on the valve-seatof the cylinder and the top edges reaching very nearly to the cover Onand throughout the entire length of the top edges of these sides isfitted a packin g-riu g or packing-strips, to be pressed against thesteam-chest cover by pressure of steam in the chest, thus preventingsteam from passing Vover iutothe space iuclosed bythe sides of thevalve. 'Ihe amount of lap required on the valve should be added asiianges at the bottom edge, bearing on the Valve-seat. The steam isexhausted from the cylinder into the space inclosed by the walls orsides of the valve, and can be passed from thence through thevalve-seat, as ordinarily done, or through the steam-chest cover, asshown in Fig. 1 at E.

l The packing-ring of the circular form of a valve is allowed tocontract, when acted upon by external pressure of steam, by cutting, as

` shown at m in Fig. 2, the wedge-piece p' tillor other cause.

to suit such contraction, thus making a tight joint at the'point ofcutting. It is only by allowing such contraction that the joint betweenthe inner side of the ring and the inner side of the channel in the edgeof the valve can be kept tight and steam prevented from passing by itinto the space inclosed by the sides or walls of the valve.

In the rectangular form of valve, as shown in Fig. 3, the packing-stripsp are pressed by external pressure of steam against the inner surfaceot' the channel holding said strips, thereby making a tight joint atthose parts. The joints between the strips, at thecorners of the valve,are kept tight by the pieces p', which bear against the ends of thestrips, adjusting themselves according to the position of the strips,and allowing for variation in the length of the strips from expansion byheat It is by the use ot' these corner pieces, p', in the rectangularform of valve that the packing-strips are rendered effective in making atightjoint between the top edges of theA valve and the steam-chestcover, thereby preventing the steam from passing over into the spaceinclosed by the sides 'or walls of the valve.

The packing-ring in the circular form of valve and the packing-strips inthe rectangular form of valve are constantly pressed up against thesteam-chest cover by springs placed underneath the ring or strips.

The valve constructed as above described can receive but little pressurefrom steam in the steam-chest, sincel the only portions subject ltopressure being the narrow space outside the packing ring or strips-onthe top edge of the valve and the amount of surface on the anges-at thebottom edge'for the required lap of the valve. This small amount ofpressure is desirable to keep the valve on its-seat, and the valve ispractically a balanced slidevalve.

'In the drawings, A shows the steam-chest cover; B, the walls ofthesteam-chest; (l, the

valve-seat; D, the arm of the valve; E, the aperture through thesteam-chest cover. V

shows the valve; V', the space within the valve; p, the ring or strippacking; p', the

wedge or corner pieces m, the cutting of the ring-packing. 1 r show thesprings underneath'the packing.-

What I claim as my invent-ion, and desire t0 secure by Letters Patent,is-

1. The paeking-wedgep in the packing-ring p, Where the packing-ring issubjected to eX- ternal pressure, or is contracted in order to makethejoint tight for which it; is used.

2. The corner pieces, p', for making a tight `joint: at the ends of thepacking-strips, where said strips are required to be placed in amatangular valve or in au angular position.

GEORGE FRED. MORSE.

Witnesses:

WM. HENRY CLIFFORD, HENRY C. HOUSTON.

